This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Divalent metals such as iron and manganese are essential to may biochemical processes. Cellular divalent metal homeostasis requires specialized transmembrane transporters. We aim to determine the atomic structure of a bacterial NRAMP transporter as a step in understanding how NRAMP transporters select and transport divalent cations using a proton gradient.